Lowered extracellular potassium levels will lower the heart rate because
A)the resting membrane potential is hyperpolarized.
B)ectopic action potentials occur.
C)action potential amplitude declines.
D)more sodium channels open.
E)it blocks calcium channels.

Question

Quizplus · Accepted Answer

Lowered extracellular potassium levels cause hyperpolarization of the resting membrane potential, making it more difficult for cardiac cells to reach the threshold for action potentials, thus lowering the heart rate.

Lowered Extracellular Potassium Levels Will Lower the Heart Rate Because